Project Summary Cerebral palsy (CP) is the most common cause of severe motor impairment in children, affecting 3 per 1000 in the US and internationally. Motor impairment is the primary defining feature, but co-occurring developmental disabilities are frequent and lead to a complex array of problems. Approximately 60% of children with CP have some type of communication disorder, which may include dysarthria and its associated speech intelligibility deficits; language and/or cognitive impairments; or a combination of both speech and language/cognitive problems. Advancing our understanding of communication abilities is a priority area in CP research. However, heterogeneity among children with CP makes the study of speech, language, and communication and its development difficult, necessitating the use of prospective longitudinal methods where each child is his/her own control to allow for direct connection between early speech-language markers and later development. We began such work 10 years ago, following over 90 children with CP who were as young as 2 years at the onset of the study. The long-term goal of our research is to generate theoretically driven, empirically validated longitudinal models of speech and language development in CP that can be used to predict outcomes, test interventions, and guide treatment decisions. Over the past two funding cycles, we have developed a classification model of speech-language profile groups among children with CP, which we are using to predict outcomes. Results suggest that children in more advanced profile groups at 2 years of age remain in more advanced profile groups in later childhood. Also, those who are producing speech by 2 years make faster gains in intelligibility and utterance length and have better speech production later than those who begin speaking at older ages. We are also developing speech and language growth curves and using data to create models of profile group membership based on development across childhood. Data indicate that children with CP are still changing through 10 years of age and have not yet reached developmental endpoints. Progress is currently limited by two key barriers, addressed in this application: 1.) longitudinal speech and language development data prior to 2 years of age have never been gathered for children with CP. These data are necessary to refine our ability to predict speech-language outcomes beginning at the earliest possible age and establish prognostic indicators that can inform intervention decision-making; and 2.) longitudinal data beyond 10 years of age have never been gathered, but are needed to quantify rates and limits of change in speech-language variables through the full course of development so that we can develop predictive models of age-based endpoints that guide interventions and improve outcomes. Toward this end, we will collect new longitudinal data on our existing cohort of children with CP to the age of 15 years, and we will collect new longitudinal data on a new cohort of very young children with CP beginning at 12 months of age to address the following two specific aims: Aim 1 - To establish and validate prognostic indicators beginning at 12 months of age that have predictive value for later speech-language development in children with CP. Aim 2 - To develop comprehensive predictive models of speech-language development up to 15 years of age in children with CP. Results will advance the development and validation of longitudinal models of speech and language growth in children with CP, quantifying of rates and limits of change for select speech and language variables. Results will enable us to predict outcomes for children from 1-15 years of age, which will have implications for intervention decision-making and for creation of interventions to enhance quality of life for children with CP.